Tenascin is an extracellular glycoprotein which was discovered as an antigen defined by the antibody showing unique staining properties different from that to collagen type V by Chiquet and Fambrough in 1984 in their attempt to prepare a monoclonal antibody against collagen type V (see Journal of Cell Biology, Vol. 98, pp. 1926-1936 & 1937-1946 (1984)).
Tenascin was considered at first to be a carcinoembryonic antigen. Thereafter, several monoclonal antibodies against tenascin were prepared, and development of tenascin in various cancers was examined.
In recent years, existence of tenascin in serum was revealed (see Cancer Research, Vol. 51, pp. 4853-4858 (1991)).
Several methods for quantitatively determining tenascin have hitherto been reported. For example, (1) a method for determining tenascin in the human osteosarcoma tissue and the chicken embryonic brain by ELISA using an M1 monoclonal antibody against chicken tenascin and a rabbit polyclonal antibody (see Annals New York Academy of Science, Vol. 580, pp. 260-275 (1990)) and (2) a method comprising mixing the serum of a melanoma-bearing patient and a monoclonal antibody against human tenascin and subsequently reacting the mixture with tenascin bound to a solid phase and determining the monoclonal antibody bound to the tenascin on the solid base after the reaction according to the indirect RIA method (see Cancer Research, Vol. 51, pp. 4853-4858 (1991)) are known.
However, either of these methods is to determine tenascin in plasma or serum and, besides, involves many problems. For example, since method (1) uses antibodies against chicken tenascin and the rate of cross reaction in the measurement of tenascin in human tissues is not established, the result obtained cannot be decided to be an accurate value. According to method (2), the inhibition of binding of antibodies to the tenascin bound to a solid phase by the action of tenascin in the serum sample is merely expressed in terms of percent inhibition so that an accurate amount of tenascin is not obtained.